This kit is for engines with a 6V 50cc cylinderhead (20/23mm valves).
Aluminum cylinder: 63mm long and with 47mm bore.
For crankshafts with 41,3mm stroke.
Police version marked with 49cc.
This kit works fine with a 18/20mm carb.
Honda 6V ST50 Z50 + Jincheng Dax Monkey